In modern society, artifacts are created and archived at an increasingly growing rate. Specifically, the proliferation of the Internet and the continued growth and simplification of web publishing tools has greatly facilitated sharing and publication of ideas and stories online by technologically unsophisticated users. These stories and ideas are frequently enhanced by the inclusion of photographs and images which support the viewpoints and messages of the authors. In many cases, through the use of photo editing software, the images can become highly manipulated, with portions added, removed, or otherwise altered. These manipulations often not only indicate the usage of the images, but also affect the meanings conveyed by the images and reflect the beliefs of the authors. A history of the manipulations over an image can be revealing of the evolution in temperament, viewpoint, and attitudes of the general public over time.
FIG. 16a shows a famous photograph, Raising the Flag on Iwo Jima, which was taken by Joe Rosenthal shortly after the World War II battle in Iwo Jima in 1945. Immediately after it was shot, the image was reproduced in newspapers all across the United States. The wide distribution of the image served to invoke national pride and convey a highly patriotic and supportive view of the United States' use of military force. In FIG. 16b, a photomontage made for an anti-Vietnam War poster in 1969 by Ronald and Karen Bowen, replaced the flag in the soldiers' hands with a giant flower. The objective here was to take the originally pro-war image and subvert its meaning into anti-war imagery.
The challenge of identifying whether or not two images are copies of each other has been addressed in recent research efforts in image near-duplicate detection. As the term “near” would imply, these research efforts aim to detect pairs where the duplication may not be exact. Thus the methods of copy identification are robust against a variety of distortions, such as cropping, scale, and overlay. However, these detection methods do not specifically address the manipulations that one image has been subjected to arrive at the other images.
Another field, image forensics, also takes into account of the manipulation for identifying whether or not any manipulations of an image have taken place. Approaches in this field can involve checking the consistency of various regions of the image for artifacts induced by the physics or the peculiarities of the acquisition and compression processes. Such cues can be used to identify the camera used to take a photograph or if two regions of a photograph are derived from separate sources. However, again, image forensics focus on the evaluation of similarities between two images, and are not concerned with detecting the manipulations of images in the context of a plurality of various instances of the same image.
It would be valuable to identify the original image in a collection of related images, and desirable to track the usage of the images and their evolution over time, and to help design systems that enhance image searching, browsing, and retrieval using information obtained from such archaeological digs. Therefore, there is a need for developing techniques for analyzing related images and determining plausible manipulation history among the images.